[Antiphospholipid antibody/cofactors. What are they? Why, when and how to search for them? Is treatment justified?]

Antiphospholipid antibodies are a wide family of antibodies, dominated by lupus anticoagulant (LA) and anti-cardiolipin antibodies (aCL), encountered in various circumstances. Unnecessary laboratory tests can be avoided by carefully weighing the indications, especially regarding patient age. Three steps are required to demonstrate LA: screening, mixing studies, then confirmation by neutralization tests. Two coagulation tests at least should be performed aCL are detected with ELISA kits using plates coated with cardiolipin. Due to the large number of kits available and to the lack of agreement on cut-off values, all laboratories must indicate their own standards. Other kits use plates coated with a mixture of phospholipids. Recent data suggest that pathogenic aPL are more specifically directed against phospholipid-associated proteins rather than towards phospholipids. In the future, tests for aCL might be replaced by tests for beta 2-glycoprotein I. The presence of aPL requires a specific treatment only in patients presenting clinical manifestations thought to be aPL-induced (thromboses, fetal losses). Long term warfarin aimed at an INR of 3-3.5 is effective for the secondary prevention of thrombosis. In primary APS, prevention of recurrent miscarriages is frequently achieved by a combination of subcutaneous heparin plus aspirin.